1、Designation: C359 08C359 13Standard Test Method forEarly Stiffening of Hydraulic Cement (Mortar Method)1This standard is issued under the fixed designation C359; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of early stiffening in hydraulic-cement mortar.1.2 The values stated in SI units are
3、 to be regarded as standard. The values given in parentheses are mathematical conversionsto inch-pound units that are provided for information only and are not considered standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the res
4、ponsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. (WarningFresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin andtissue upon prolonged exposure. The us
5、e of gloves, protective clothing, and eye protection is recommended. Wash contact areawith copious amounts of water after contact. Wash eyes for a minimum of 15 min.Avoid exposure of the body to clothing saturatedwith the liquid phase of the unhardened material. Remove contaminated clothing immediat
6、ely after exposure.)Warning: Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolongedexposure.21.4 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes(excluding those in tables
7、and figures) shall not be considered as requirements of the standard.2. Referenced Documents2.1 ASTM Standards:3C183 Practice for Sampling and the Amount of Testing of Hydraulic CementC185 Test Method for Air Content of Hydraulic Cement MortarC187 Test Method for Amount of Water Required for Normal
8、Consistency of Hydraulic Cement PasteC305 Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic ConsistencyC670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction MaterialsC778 Specification for SandC1005 Specification for Reference Mass
9、es and Devices for Determining Mass and Volume for Use in the Physical Testing ofHydraulic CementsD1193 Specification for Reagent WaterE2251 Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids3. Terminology3.1 Definitions:3.1.1 early stiffening, nthe early developme
10、nt of stiffness in the working characteristics of a hydraulic-cement paste, mortar,or concrete; varieties include false set and flash set.3.1.2 false set, nthe early development of stiffness in the working characteristics of a hydraulic-cement paste, mortar, orconcrete without the evolution of much
11、heat, which stiffness can be dispelled and plasticity regained by further mixing withoutaddition of water; also known as “grab set,” “ premature stiffening,” “hesitation set,” and “rubber set.”3.1.3 flash set, nthe early development of stiffness in the working characteristics of a hydraulic-cement p
12、aste, mortar, orconcrete, usually with the evolution of considerable heat, which stiffness cannot be dispelled nor can the plasticity be regained byfurther mixing without addition of water; also known as “quick set.”1 This test method is under the jurisdiction of ASTM Committee C01 on Cement and is
13、the direct responsibility of Subcommittee C01.30 on Time of Set.Current edition approved June 1, 2008Dec. 1, 2013. Published June 2008January 2014. Originally approved in 1955. Last previous edition approved in 20072008 asC359 07.C359 08. DOI: 10.1520/C0359-08.10.1520/C0359-13.2 Section on Safety, M
14、anual of Cement Testing, Annual Book of ASTM Standards, Vol 04.01.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM web
15、site.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prio
16、r editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1942
17、8-2959. United States14. Summary of Test Method4.1 A mortar is prepared with the cement to be tested, using specified quantities of cement, standard sand, and an amount ofwater that will produce a mortar with an initial penetration of 46 6 3 mm, using the modified Vicat apparatus. Measurements ofpen
18、etration are made at stipulated intervals after the beginning of the mixing procedure. Upon completion of the first series ofpenetration measurements, the mortar is returned to the mixer to be remixed. Following the remix procedure, an additionalpenetration, termed the remix penetration, is determin
19、ed.The report is a tabulation of the penetration measurements and the amountof mixing water used.5. Significance and Use5.1 The purpose of this test method is to determine the degree to which a cement mortar develops early stiffening. It is intendedfor use by those interested in methods for determin
20、ing the potential early stiffening of hydraulic cement.5.2 When used for estimating the relative tendency of a cement to manifest early stiffening, a judgment may be made bycomparing the behavior in the penetration series (see 10.4.1 and 10.4.2) and the remix procedure (see 10.4.3) to differentiate
21、arelatively less serious and less persistent tendency to early stiffening (false set) from one that is more persistent and, consequently,more serious (flash set).5.3 Severe false setting in a cement may cause difficulty from a placing and handling standpoint, but it is not likely to causedifficultie
22、s where concrete is mixed for a longer time than usual, as usually occurs in transit mixing, or where it is remixed priorto placing or transporting, in concrete pumping operations. It is most likely noticed where concrete is mixed for a short period oftime in stationary mixers and transported to the
23、 forms in non-agitating equipment, as on some paving jobs, and when concrete ismade in an on-site batch plant.5.4 Cements with severe false setting usually require slightly more mixing water to produce the same consistency, which mayresult in slightly lower strengths and increased drying shrinkage.5
24、.5 Early stiffening resulting from false set is not likely to cause a cement to fail the applicable time of setting requirement.5.6 Early stiffening resulting from flash set, depending on severity, can cause a cement to fail the applicable time of settingrequirement.6. Apparatus6.1 Vicat Apparatus,
25、conforming to the requirements of Fig. 1 in Test Method C187, with the following modifications:6.1.1 The 1-mm needle shall be replaced by a mass, such that the total mass of the 10-mm plunger, indicator, and added massshall be 400 6 0.5 g.6.2 Spoon, conforming to the requirements of Test Method C185
26、.6.3 Mixer, Bowl, Paddle, and Scraper, conforming to the requirements of Practice C305.6.4 Glass Graduates, 200 or 250 mL capacity, conforming to the requirements of Specification C1005.6.5 Masses and Mass Determining Devices, conforming to the requirements of Specification C1005. The devices fordet
27、ermining mass shall be evaluated for precision and accuracy at a total load of 1000 g.6.6 Thermometer, ASTM No. S12C or S12F, conforming to the requirements of Specification E2251.6.7 Flat Trowel, having a sharpened straight-edged steel blade 100 to 150 mm in length. The edges when placed on a plane
28、surface shall not depart from straightness by more than 1 mm.6.8 Clock Timer, having a readability to the nearest second.6.9 Containers, approximately 50 by 50 by 150 mm (2 by 2 by 6 in.) inside dimensions (Fig. 1). These containers, which mayFIG. 1 Container for Early Stiffening TestsC359 132be mad
29、e of any suitable materials such as sheet metal or plastic, shall be rigid, watertight, and at least 50 mm (2 in.) deep.7. Reagents and Materials7.1 Standard Sand, 20-30 and Graded, conforming to the requirements of Specification C778.7.2 Mixing WaterPotable water is satisfactory for routine tests.
30、For all referee and cooperative tests, reagent water conformingto the requirements of Specification D1193 for Type III or Type IV grades of reagent water shall be used.8. Sampling8.1 When the test is part of acceptance testing, sample the cement in accordance with Practice C183.9. Conditioning9.1 Ma
31、intain the temperature of the room, dry materials, paddle, bowl, and containers at 23.0 6 3.0 C.9.2 The relative humidity of the mixing room shall not be less than 50 %.10. Procedure10.1 BatchMix at one time 600 g of cement, 300 g of graded standard sand, 300 g of 20-30 standard sand, and an amounto
32、f water that produces a mortar with an initial penetration of 46 6 3 mm.10.2 Mixing of MortarMix in the mechanical mixer as follows:10.2.1 Place the sand and cement in the dry bowl, and mix the dry materials for a few seconds with the spoon.10.2.2 Place the bowl in the mixer, set the paddle in place
33、, and mix the dry materials for 10 s at a slow speed (140 6 5 r/min).10.2.3 With the mixer operating at a slow speed (140 6 5 r/min), add the entire quantity of mixing water within 5 s. Stop themixer, quickly change to a medium speed (285 6 10 r/min), and continue the mixing for 1 min, timing from t
34、he first addition ofwater.10.2.4 Stop the mixer, scrape the sides of the mixing bowl with the rubber scraper, and quickly place the thermometer in themortar. Allow it to stand undisturbed for the remainder of a 45-s interval from the time of stopping the mixer.10.2.5 Read the temperature, remove the
35、 thermometer, start the mixer, and mix for 15 s at a medium speed (285 6 10 r/min).If the mortar temperature is not in the range from 23 6 2.0 C, discard the batch and adjust the temperature of the water or sand,or both, to give the required temperature.10.3 Filling Container:10.3.1 Immediately afte
36、r completion of the mixing, remove the bowl from the mixer and with a spoon, uniformly distribute aportion of the mortar into the container until the container is heaping full. Quickly and gently place each spoonful of mortar inthe container. When removing the mortar from the bowl, do not remove the
37、 material pushed up on the side of the bowl by thepaddle. After the container has been filled, reassemble the mixer, cover the bowl with a lid, and retain the remaining mortar fora remix test to be performed later. To compact the mortar in the container, lift the container approximately 80 mm (3 in.
38、) from thetable with both hands and rap it twice against the surface of the table.10.3.2 With the leading edge slightly raised, strike off the mortar with one stroke of the trowel along the length of the container.Then remove the excess mortar by means of a sawing motion with the straightedge of the
39、 trowel along the length of the containerin a direction opposite to that used in striking off. Then, smooth the surface of the mortar with a single stroke of the trowel.10.4 Penetration Tests:10.4.1 After filling the container, immediately place the 10-mm plunger of the modified Vicat apparatus in c
40、ontact with thesurface of the mortar at the midpoint of the container on the longitudinal center line. Set the movable indicator at zero. Releasethe plunger 3 min after the beginning of the wet mixing and record, as the initial penetration, the depth in millimetres to whichthe plunger has settled be
41、low the surface 10 s after being released. If the plunger does not settle to a depth of 46 6 3 mm, discardthe batch and adjust the quantity of water to produce the required consistency.10.4.2 Immediately withdraw and clean the plunger. In a similar manner, determine, after moving the Vicat apparatus
42、 to thedesired location, the penetrations at intervals of 5, 8, and 11 min after the beginning of mixing. Do not move the filled containeruntil these measurements are completed. Make all penetrations along the longitudinal center line of the container. Obtain 5 and8-min penetrations at a distance of
43、 approximately 40 mm (112 in.) from each end of the container, respectively, and determine the11-min penetration at a point approximately midway between the points at which the initial and 5-min penetrations weredetermined.10.4.3 At the completion of the measurement of the 11-min penetration, immedi
44、ately return the mortar in the container to thebowl. Start the mixer, raise the bowl into mixing position, and remix the contents of the bowl at medium speed (285 6 10 r/min)for 1 min. Fill a clean container as outlined in 10.3.1 and 10.3.2, and determine the penetration 45 s after completion of mix
45、ing.11. Calculation11.1 Early Stiffening AmountThe change in penetration from the initial penetration to the 11 min penetration.11.1.1 Calculate as follows: A D, where:C359 133A = Initial PenetrationB = Penetration at 5 minC = Penetration at 8 minD = Penetration at 11 minE = Penetration after REMIX1
46、1.1.2 Report to the nearest mm.11.2 Average Early Stiffening RateAn average of the rate of penetration change between each set of measurements.11.2.1 Calculate as follows:A2B2 1B2C3 1C2D33where A,B,C,D are as defined in 11.1.1.11.2.2 Report to the nearest 0.1 mm/min.11.3 Early Stiffening RecoveryThe
47、 percent penetration recovery accomplished with the REMIX procedure.11.3.1 Calculate as follows:100*EAwhere E and A are as defined in 11.1.1. (See Note 2)11.3.2 Report to the nearest percent.12. Report12.1 Report the measured and calculated values as shown below:Mixing Water _mLInitial penetration _
48、mm5-min penetration _mm8-min penetration _mm11-min penetration _mmRemix penetration _mmEarly Stiffening Amount _mmAverage Early Stiffening Rate _mm/minEarly Stiffening Recovery _%13. Precision and Bias413.1 Early Stiffening Amount13.1.1 The single-operator standard deviation has been found to be 1.8
49、 mm over a range from 35 to 49 mm. Therefore, resultsof two properly conducted tests by the same operator on the same material are not expected to differ by more than 5 mm. (SeeNote 3)13.1.2 The multilaboratory standard deviation has been found to be 2.5 mm over a range from 35 to 49 mm. Therefore, resultsof two properly conducted tests from two different laboratories on samples of the same cement are not expected to differ by morethan 7 mm. (See Note 3)13.2 Average Early Stiffening Rate13.2.1 The single-operator standard deviation has been fou
